如果你正在使用片段，并且你想在Android中以编程方式更改应用程序语言，请使用此方法

  public void setLocale(Activity activity, String languageCode) {
    Locale locale = new Locale(languageCode);
    Locale.setDefault(locale);
    Resources resources = activity.getResources();
    Configuration config = resources.getConfiguration();
    config.setLocale(locale);
    resources.updateConfiguration(config, resources.getDisplayMetrics());
     SettingsFragment settingsFragment = new SettingsFragment();
     FragmentManager fragmentManager = requireActivity().getSupportFragmentManager();
     FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    activity.overridePendingTransition(0,0);
     fragmentTransaction.replace(R.id.main, settingsFragment).commit();
}

这样叫它

setLocale(requireActivity(),"fr");

只需要用你的片段名改变SettingsFragment，在你调用方法的地方，这基本上是刷新布局来获得视图上的新字符串 如果你想在另一个类上设置这个方法只需像这样添加context

public void setLocale(Activity activity, String languageCode,Context context) {
    Locale locale = new Locale(languageCode);
    Locale.setDefault(locale);
    Resources resources = activity.getResources();
    Configuration config = resources.getConfiguration();
    config.setLocale(locale);
    resources.updateConfiguration(config, resources.getDisplayMetrics());
    SettingsFragment settingsFragment = new SettingsFragment();
    FragmentManager fragmentManager = ((AppCompatActivity) context).getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    activity.overridePendingTransition(0,0);
    fragmentTransaction.replace(R.id.main, settingsFragment).commit();
}

您可以要求用户在第一个屏幕中选择语言并将其保存在SharedPreferences中

SharedPreferences.Editor editor = getSharedPreferences("data", MODE_PRIVATE).edit();
editor.putString("lang", "si");
editor.apply();
    
recreate();

然后你可以在应用程序中的每个Activity中使用它。这里我设置了英语和僧伽罗语。

@Override
protected void attachBaseContext(Context base) {
    SharedPreferences prefs = base.getSharedPreferences("uinfo", MODE_PRIVATE);
    String restoredText = prefs.getString("lang", "No name defined");

    if (restoredText.equals("si")){
        super.attachBaseContext(LocaleHelper.localeUpdateResources(base, "si"));
    }else{
        super.attachBaseContext(LocaleHelper.localeUpdateResources(base, "en"));
    }
}

这是你的localUpdateResources方法。把它放在LocalHelper类中

public class LocaleHelper {
    public static Context localeUpdateResources(Context context, String languageCode) {

        Context newContext = context;

        Locale locale = new Locale(languageCode);
        Locale.setDefault(locale);

        Resources resources = context.getResources();
        Configuration config = new Configuration(resources.getConfiguration());

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {

            config.setLocale(locale);
            newContext = context.createConfigurationContext(config);

        } else {

            config.locale = locale;
            resources.updateConfiguration(config, resources.getDisplayMetrics());
        }

        return newContext;

    }
}

唯一完全适合我的解决方案是结合Alex Volovoy的代码和应用程序重启机制:

void restartApplication() {
    Intent i = new Intent(MainTabActivity.context, MagicAppRestart.class);
    i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    MainTabActivity.context.startActivity(i);
}


/** This activity shows nothing; instead, it restarts the android process */
public class MagicAppRestart extends Activity {
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        finish();
    }

    protected void onResume() {
        super.onResume();
        startActivityForResult(new Intent(this, MainTabActivity.class), 0);         
    }
}

我终于弄清楚如何设置它工作在两个=N安卓版本。

用你自己的抽象类扩展AppCompatActivity，比如:

abstract class MLAppCompatActivity : AppCompatActivity() {
  override fun attachBaseContext(newBase: Context?) {
    super.attachBaseContext(LocaleHelper.wrap(newBase))
  }

  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) {
        LocaleHelper.wrap(this)
    }
  }
}

attachBaseContext在Android >=N版本上被调用，这样activity将使用正确的上下文。在Android <N上，我们必须以另一种方式调用这个函数，在设置内容视图之前。因此，我们重写onCreate函数来设置正确的上下文。 意思是，每当你创建一个新的Activity时，你必须扩展你的抽象类。比如这个:

class TermsActivity : MLAppCompatActivity() {
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_terms)
  }
}

最后LocaleHelper是这样的:

import android.annotation.TargetApi;
import android.content.Context;
import android.content.ContextWrapper;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.os.Build;
import android.util.DisplayMetrics;

import com.at_zone.constants.SharedPreferencesKeys;

import java.util.Locale;

public class LocaleHelper extends ContextWrapper {

    public LocaleHelper(Context base) {
        super(base);
    }

    public static Context wrap(Context context) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(
                SharedPreferencesKeys.SHARED_PREFERENCES, Context.MODE_PRIVATE
        );
        String language = sharedPreferences.getString(SharedPreferencesKeys.CURRENT_LANGUAGE, "default");
        if (!language.equals("default")) {
            Configuration config = context.getResources().getConfiguration();
            if (!language.equals("")) {
                Locale locale = new Locale(language);
                Locale.setDefault(locale);
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                    setSystemLocale(config, locale);
                } else {
                    setSystemLocaleLegacy(context, config, locale);
                }
                config.setLayoutDirection(locale);
                context = context.createConfigurationContext(config);
            }
            return new LocaleHelper(context);
        }
        return context;
    }

    public static String getSystemLanguage(Context context) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            return getSystemLocale(context).getLanguage().toLowerCase();
        } else {
            return getSystemLocaleLegacy(context).getLanguage().toLowerCase();
        }
    }

    public static Locale getSystemLocaleLegacy(Context context) {
        Configuration config = context.getResources().getConfiguration();
        return config.locale;
    }

    @TargetApi(Build.VERSION_CODES.N)
    public static Locale getSystemLocale(Context context) {
        return context.getResources().getConfiguration().getLocales().get(0);
    }

    public static void setSystemLocaleLegacy(Context context, Configuration config, Locale locale) {
        config.locale = locale;
        Resources res = context.getResources();
        DisplayMetrics dm = res.getDisplayMetrics();
        res.updateConfiguration(config, dm);
    }

    @TargetApi(Build.VERSION_CODES.N)
    public static void setSystemLocale(Configuration config, Locale locale) {
        config.setLocale(locale);
    }

}

这里列出的解决方案没有一个对我有用。

如果AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES)，语言没有在android >= 7.0上切换

这个LocaleUtils工作得很好: https://gist.github.com/GigigoGreenLabs/7d555c762ba2d3a810fe

LocaleUtils

public class LocaleUtils {

public static final String LAN_SPANISH      = "es";
public static final String LAN_PORTUGUESE   = "pt";
public static final String LAN_ENGLISH      = "en";

private static Locale sLocale;

public static void setLocale(Locale locale) {
    sLocale = locale;
    if(sLocale != null) {
        Locale.setDefault(sLocale);
    }
}

public static void updateConfig(ContextThemeWrapper wrapper) {
    if(sLocale != null && Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
        Configuration configuration = new Configuration();
        configuration.setLocale(sLocale);
        wrapper.applyOverrideConfiguration(configuration);
    }
}

public static void updateConfig(Application app, Configuration configuration) {
    if(sLocale != null && Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR1) {
        //Wrapping the configuration to avoid Activity endless loop
        Configuration config = new Configuration(configuration);
        config.locale = sLocale;
        Resources res = app.getBaseContext().getResources();
        res.updateConfiguration(config, res.getDisplayMetrics());
    }
}
}

将此代码添加到应用程序

public class App extends Application {
public void onCreate(){
    super.onCreate();

    LocaleUtils.setLocale(new Locale("iw"));
    LocaleUtils.updateConfig(this, getBaseContext().getResources().getConfiguration());
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    LocaleUtils.updateConfig(this, newConfig);
}
}

活动中的代码

public class BaseActivity extends AppCompatActivity {
    public BaseActivity() {
        LocaleUtils.updateConfig(this);
    }
}

androidx。Appcompat: Appcompat用户，以上解决方案将在1.3.0版本后工作。 就像这里提到的。